The present invention relates to organosilicon compositions which bear at least one silicon-bonded, aliphatically unsaturated hydrocarbonoxy radical. In one aspect the present invention relates to heat-curable compositions comprising an organosilicon polymer bearing at least one silicon-bonded, aliphatically unsaturated phenoxy or carbonoxy radical and an organosilicon curing agent bearing at least two silicon-bonded hydrogen
Organosilicon compositions bearing silicon-bonded alkenyl radicals, such as vinyl, are very useful, such as in a heat-curable composition, and are well known in the silicon polymer art. It is also well known that such compounds are relatively expensive compared to the organosilicon compositions which bear alkoxy and/or hydroxy curing sites and which are well known in moisture-curing compositions. There is a need for a less expensive, aliphatically unsaturated organosilicon composition which is curable with heat and which is stable in the presence of moisture.
Organosilicon compositions bearing the silicon-oxygen-carbon linkage are relatively easy to prepare and certain aliphatically unsaturated hydrocarbonoxy radicals bonded to silicon through an oxygen atom, such as allyloxy and vinyloxy, are well known. Unfortunately, these well-known hydrocarbonoxy radicals are also hydrolytically unstable and, indeed, are useful as hydrolyzable sites in a moisture-curing composition. However, hydrolytic instability of an aliphatically unsaturated hydrocarbonoxy radical is undesirable when said radical is to be used as a permanent radical such as an endblocking radical or when said aliphatic unsaturation is to be used in a heat-curing composition to effect a cure of the composition.
Silicon-containing compositions bearing at least one silicon-bonded alkenyloxy radical wherein the aliphatic unsaturation of the alkenyloxy radical is not adjacent to the alpha carbon of said radical are disclosed by Strain, et al., U.S. Pat. No. 2,394,642; Garner, U.S. Pat. No. 2,396,692; Robie, et al., U.S. Pat. No. 2,438,520; Robie, U.S. Pat. No. 2,481,349; Smith, U.S. Pat. No. 2,815,300; deBenneville, et al., U.S. Pat. No. 2,865,884; Bailey, U.S. Pat. No. 2,909,549, and Beers, et al., U.S. Pat. No. 3,541,044. However, these references disclose neither the organosilicon compositions of this invention nor the heat-curable compositions comprising the alkenyloxy-containing organosilicon compositions of this invention and an organosilicon curing agent bearing at least one silanic hydrogen, i.e. silicon-bonded hydrogen atom.